This is a never fired but installed Rock River Arms A4 upper. It has a 20" HBAR chrome-moly barrel with a 1/9" twist and a factory military-style muzzle brake. It is a post-ban so there is no bayonet lug.
It has never been fired but does have marks on the mounting blocks where it slid in the lower receiver. There are no other significant marks or scratches.
The factory number is AR0400B for the upper and AR0117MS for the muzzle brake.
It does not come with bolt, bolt carrier, or charging handle.
Email me for pictures.
I want $275 for it shipped. I will take Paypal if you split the fees with me (1.5%) or money orders.